1. Field of the Invention
The invention relates to foundry practice, and more particularly to vacuum metal die-casting apparatus of the type intended preferably for producing precision castings from refractory and highly reactive metals and alloys, such as those based on titanium or zirconium.
2. Description of the Prior Art
British Patent Specification No. 914,508 discloses a metal die-casting apparatus which comprises a frame having mounted thereon an air-tight housing common to both melting and casting chambers. Enclosed in said common housing are two stationary vertical plates interconnected by guide columns. Mounted in the guide columns is a mobile plate provided with a reciprocating drive means. Within said air-tight housing is an electrode holder mounted over a crucible for rotation about a horizontal axis and it is provided with a drive means for providing rotation to said electrode holder.
Underneath the crucible is a funnel placed in the pouring orifice of a pressure chamber housing.
The pressure chamber housing is built into a stationary plate which carries one half of a die, the second half thereof being secured to a mobile plate. The pressure chamber incorporates a means for the forced supply of metal into the die, and said means being basically a piston secured to a piston rod of a hydraulic cylinder.
It is a matter of practical knowledge that when metal is forced into the die there is insufficient rigidity of connection between the two half-dies so that flash is invariably formed at the parting planes of the die, the casting then losing accuracy of size and/or shape.
Further development of the machine-building industry generates higher demands for large quantities of metal die-casting blanks. Particularly severe problems are encourtered in known apparatus for die casting precision blanks from highly reactive metals and alloys, such as titanium- or zirconium-based alloys and a solution to these problems is a central necessity.